An RF detector is a somewhat ambiguous definition given to a range of RF probes, RF detectors, and RF demodulators. This term could apply to virtually any sensor that responds to RF energy. The term RF detector comes from the original Morse code coherer detectors, which merely needed to determine if an RF signal was present or not in the transmission medium.

Modern RF detector technologies used in commercial, military, and scientific applications include quadrature detectors, ratio detectors, phase detectors, product detectors, envelope detectors, and etc. These types of RF detectors are used in demodulation circuitry, and could also be called a RF demodulator. This is the most common use of the term “RF detector”.